Table 2.
Studies examining the influence of equipment scaling on children’s sport performance
| Sport | References | Modification | Population studied | Primary outcome: positive (Y/N) | Main finding |
|---|---|---|---|---|---|
| Basketball | Szyman et al. [8] | Ball mass and diameter | 11 years, disabled/wheelchair | Y | Children displayed more accurate shooting when using smaller and lighter basketballs from the 2 distances examined: 13 ft and 10 ft from the ring |
| Arias [11] | Ball mass | 9–11 years, intermediate | Y | The number of attempted lay-ups increased when children played with the lighter ball (440 g) compared with a regulation ball (485 g) and a heavier ball (540 g) during matches | |
| Arias [12] | Ball mass | 9–11 years, intermediate | Y | Shot accuracy and shot efficacy was greater when playing with a lighter ball (440 g) compared with a regulation ball (485 g) and a heavier ball (540 g) during matches | |
| Arias et al. [13] | Ball mass | 9–11 years, intermediate | N | No significant differences were found between 3 ball types (440, 485 and 540 g) for the number of attempted shots and number of successful shots from any distance during matches | |
| Arias et al. [14] | Ball mass | 9–11 years, intermediate | Y | Children passed the ball more, displayed more pass receptions and dribbled more often when using a lighter ball (440 g) compared with a regulation ball (485 g) and a heavier ball (540 g) during matches | |
| Arias et al. [15] | Ball mass | 9–11 years, intermediate | Y | Frequency of shot attempts and the number of successful shots were greater with the lighter ball (440 g) compared with a regulation ball (485 g) and a heavier ball (540 g) during matches | |
| Arias et al. [16] | Ball mass | 9–11 years, intermediate | Y | Children experienced more one-on-one situations when playing with the lighter ball (440 g) compared with a regulation ball (485 g) and a heavier ball (540 g) during matches | |
| Regimball et al. [9] | Ball dimensions | 10 years, beginners | N | No difference in performance (free-throw shooting) between ball types; however, performance was better for the particular ball that children preferred. 62 % of children preferred using the smallest ball and 45 % preferred using a ball that is smaller than the one they usually use | |
| Chase et al. [17] | Basket height and ball dimensions | 6–7 yearsa | Y | Children were more successful when shooting to the lower basket (2.44 m) compared with the higher basket (10 ft). Self-efficacy was also higher when shooting to the lower basket (3.05 m). Ball size had no influence on shooting performance, but shot efficacy was greater with the smaller ball than the larger ball | |
| Satern et al. [18] | Ball mass and diameter, and basket height | 12 yearsa | Y | Lowering the basket from 3 to 2.4 m resulted in a change in shooting trajectory for free-throw shots. However, there was no assessment of how this influences shooting accuracy. Ball size had no effect on movement kinematics | |
| Cricket | Elliott et al. [19] | Pitch length | 10, 12 and 14 yearsa | Y | Children in each age group bowled more accurately at a shorter pitch length. Under-11 and under-13 bowlers displayed techniques that were seemingly more prone to injuries when bowling on a full-length pitch as opposed to the shorter pitch. Under-15 bowlers displayed a similar technique on the full-length pitch as the shorter pitch |
| Fundamental skills | |||||
| Throwing | Burton et al. [20] | Ball diameter | 5–1 years, beginners, and adults | Y | Children and adults displayed a regression in throwing patterns when the ball size increased to a diameter that was greater than the performer’s hand width |
| Catching | Isaacs [21] | Ball diameter | 7–8 yearsa | Y | Children caught the smaller ball (6-in. diameter) with a more mature style than the larger balls (10-in. diameter) |
| Multiple sports: bowling, basketball, throwing and baseball | Wright [22] | Ball mass for all sports and baseball bat weight | 7–8 yearsa | N | 7-year-old girls were reported to perform better with lightweight equipment than heavyweight equipment during an assessment of skill 2 days following 1 practice session. Conversely, no differences were reported between equipment types for the 8-year-old girls. For boys, both 7- and 8-year-olds tended to perform better with heavyweight equipmentb |
| Tennis | Timmerman et al. [23] | Court size and net height | 9–10 years, skilled | Y | Lowering the net by 22 cm resulted in more winners, volleys and shots played at a comfortable height, and fewer shots played behind the baseline, which represents more aggressive play |
| Buszard et al. [24] | Racquet length and ball compression | 6–9 years, beginners | Y | Forehand performance (accuracy and technique) was best when using the lowest compression ball (25 % of standard ball, “red”) combined with a scaled racquet (19-in.). The ball had a greater influence on performance than the racquet | |
| Buszard et al. [25] | Racquet length and ball compression | 9–11 years, beginners | Y | Forehand performance (accuracy and technique) was better when using a low compression ball (75 % of standard ball, “green”) combined with a scaled racquet (23-in.) compared with a standard ball and a full-size racquet | |
| Kachel et al. [26] | Ball compression | 9–10 years, skilled | Y | When using the low compression ball (75 % of standard ball, “green”), as opposed to the standard ball, children played more balls at a comfortable height, approached the net on more occasions and had faster rallies | |
| Lee et al. [27] | Net height, target area, court size | 9–10 years, beginners | Y | Constantly modifying the net height, target areas and court size to create a variable practice environment led to children displaying a greater number of movement clustersc following 4 weeks of practice (600 forehands) compared with children who practiced repetitive drills with the same net height, target areas and court size | |
| Larson and Guggenheimer[28] | Ball compression and court size | 7–9 years, intermediate | Y | Skills test performance was better when using a low compression ball (75 % of standard ball)d on a scaled court compared with when using a standard ball on a full-size court | |
| Farrow and Reid [29] | Ball compression and court size | 8 years, beginners | Y | Practicing on a full-size court with a standard ball resulted in negative learning relative to practice on a scaled court and/or with a low compression ball (<50 % of standard ball, “red”)e after 5 × 30-min practice sessions. The court had a greater influence on learning than the ball | |
| Hammond and Smith [7] | Ball compression | 5–11 years, beginners | N | No differences in tennis skills tests were present between a group practicing with a low compression ball (25 % of standard ball, “red”)f and group practicing with a standard ball following 8 × 60-min practice sessions | |
| Gagen et al. [30] | Racquet length | 4–10 years, beginners | N | Although every child had one racquet that they swung better than others, the characteristics of this racquet were not related to the child’s size or strength | |
| Elliott [31] | Racquet length | 7–10 years, beginners | Y | The groups that practiced with the smallest racquets displayed superior performance on measures of tennis skill compared with the group that practiced with the larger racquet following 16 × 50-min practice sessions | |
| Volleyball | Pellett et al. [10] | Ball mass | 7th gradea | Y | No difference in the amount of improvement from pre- to post-test was found between the lighter ball group and the regulation ball group following 16 × 35-min practice sessionsg. However, the lighter ball group performed better during match play, with more correct sets and a higher average daily success rate for the set and underarm serve |
N no, Y yes
aSkill level of participants not specified
bIn the Wright [22] study, the light balls were either a plastic “fun ball” (used for bowling, throwing and baseball hitting) or a polyethylene ball (used for basketball shooting). Conversely, the heavy balls were either a softball (used for bowling, throwing and baseball hitting) or a heavier than normal basketball (538 g). The baseball bats used were a light plastic bat (156 g) and a heavier little league bat (907 g)
cMovement clusters refer to the grouping of movement patterns for each individual based on the kinematic variables of interest. Lee et al. [27] adopted this analysis method to infer the number of movement solutions that children used to perform the task
dLarson and Guggenheimer [28] provided details regarding the coefficient of restitution for the two types of balls used in their study (i.e., the ratio of relative velocity of each ball after impact with the ground to the relative velocity of each ball before impact). The coefficient of restitution for the low compression balls ranged between 0.41 and 0.46, and for the standard balls it was between 0.53 and 0.58. Thus, we calculated that the low compression balls used in this study were likely to be similar to the balls used in other studies, which were described as being “75 % of the standard ball”
eFarrow and Reid [29] describe a “red” low compression ball as <50 % compression of the standard ball, while Buszard et al. [24] described a “red” low compression ball as 25 % compression of the standard ball. The balls used in these two studies were seemingly the same
fHammond and Smith [7] do not describe the compression of the balls used in the study. However, the mass of the ball (46.08 g) indicates that it was similar to the “red” ball that was used in the Buszard et al. [24] study
gThe final 6 days of practice in the Pellet et al. [10] study involved a match-play tournament, and all participants played with the regulation volleyball. Thus, the practice intervention, whereby the two groups practiced with different sized volleyballs, was only in fact 10 days in duration